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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * zfcp device driver4 *5 * Data structure and helper functions for tracking pending FSF6 * requests.7 *8 * Copyright IBM Corp. 2009, 20239 */10 11#ifndef ZFCP_REQLIST_H12#define ZFCP_REQLIST_H13 14#include <linux/types.h>15 16/* number of hash buckets */17#define ZFCP_REQ_LIST_BUCKETS 128u18 19/**20 * struct zfcp_reqlist - Container for request list (reqlist)21 * @lock: Spinlock for protecting the hash list22 * @buckets: Array of hashbuckets, each is a list of requests in this bucket23 */24struct zfcp_reqlist {25 spinlock_t lock;26 struct list_head buckets[ZFCP_REQ_LIST_BUCKETS];27};28 29static inline size_t zfcp_reqlist_hash(u64 req_id)30{31 return req_id % ZFCP_REQ_LIST_BUCKETS;32}33 34/**35 * zfcp_reqlist_alloc - Allocate and initialize reqlist36 *37 * Returns pointer to allocated reqlist on success, or NULL on38 * allocation failure.39 */40static inline struct zfcp_reqlist *zfcp_reqlist_alloc(void)41{42 size_t i;43 struct zfcp_reqlist *rl;44 45 rl = kzalloc(sizeof(struct zfcp_reqlist), GFP_KERNEL);46 if (!rl)47 return NULL;48 49 spin_lock_init(&rl->lock);50 51 for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)52 INIT_LIST_HEAD(&rl->buckets[i]);53 54 return rl;55}56 57/**58 * zfcp_reqlist_isempty - Check whether the request list empty59 * @rl: pointer to reqlist60 *61 * Returns: 1 if list is empty, 0 if not62 */63static inline int zfcp_reqlist_isempty(struct zfcp_reqlist *rl)64{65 size_t i;66 67 for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)68 if (!list_empty(&rl->buckets[i]))69 return 0;70 return 1;71}72 73/**74 * zfcp_reqlist_free - Free allocated memory for reqlist75 * @rl: The reqlist where to free memory76 */77static inline void zfcp_reqlist_free(struct zfcp_reqlist *rl)78{79 /* sanity check */80 BUG_ON(!zfcp_reqlist_isempty(rl));81 82 kfree(rl);83}84 85static inline struct zfcp_fsf_req *86_zfcp_reqlist_find(struct zfcp_reqlist *rl, u64 req_id)87{88 struct zfcp_fsf_req *req;89 size_t i;90 91 i = zfcp_reqlist_hash(req_id);92 list_for_each_entry(req, &rl->buckets[i], list)93 if (req->req_id == req_id)94 return req;95 return NULL;96}97 98/**99 * zfcp_reqlist_find - Lookup FSF request by its request id100 * @rl: The reqlist where to lookup the FSF request101 * @req_id: The request id to look for102 *103 * Returns a pointer to the FSF request with the specified request id104 * or NULL if there is no known FSF request with this id.105 */106static inline struct zfcp_fsf_req *107zfcp_reqlist_find(struct zfcp_reqlist *rl, u64 req_id)108{109 unsigned long flags;110 struct zfcp_fsf_req *req;111 112 spin_lock_irqsave(&rl->lock, flags);113 req = _zfcp_reqlist_find(rl, req_id);114 spin_unlock_irqrestore(&rl->lock, flags);115 116 return req;117}118 119/**120 * zfcp_reqlist_find_rm - Lookup request by id and remove it from reqlist121 * @rl: reqlist where to search and remove entry122 * @req_id: The request id of the request to look for123 *124 * This functions tries to find the FSF request with the specified125 * id and then removes it from the reqlist. The reqlist lock is held126 * during both steps of the operation.127 *128 * Returns: Pointer to the FSF request if the request has been found,129 * NULL if it has not been found.130 */131static inline struct zfcp_fsf_req *132zfcp_reqlist_find_rm(struct zfcp_reqlist *rl, u64 req_id)133{134 unsigned long flags;135 struct zfcp_fsf_req *req;136 137 spin_lock_irqsave(&rl->lock, flags);138 req = _zfcp_reqlist_find(rl, req_id);139 if (req)140 list_del(&req->list);141 spin_unlock_irqrestore(&rl->lock, flags);142 143 return req;144}145 146/**147 * zfcp_reqlist_add - Add entry to reqlist148 * @rl: reqlist where to add the entry149 * @req: The entry to add150 *151 * The request id always increases. As an optimization new requests152 * are added here with list_add_tail at the end of the bucket lists153 * while old requests are looked up starting at the beginning of the154 * lists.155 */156static inline void zfcp_reqlist_add(struct zfcp_reqlist *rl,157 struct zfcp_fsf_req *req)158{159 size_t i;160 unsigned long flags;161 162 i = zfcp_reqlist_hash(req->req_id);163 164 spin_lock_irqsave(&rl->lock, flags);165 list_add_tail(&req->list, &rl->buckets[i]);166 spin_unlock_irqrestore(&rl->lock, flags);167}168 169/**170 * zfcp_reqlist_move - Move all entries from reqlist to simple list171 * @rl: The zfcp_reqlist where to remove all entries172 * @list: The list where to move all entries173 */174static inline void zfcp_reqlist_move(struct zfcp_reqlist *rl,175 struct list_head *list)176{177 size_t i;178 unsigned long flags;179 180 spin_lock_irqsave(&rl->lock, flags);181 for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)182 list_splice_init(&rl->buckets[i], list);183 spin_unlock_irqrestore(&rl->lock, flags);184}185 186/**187 * zfcp_reqlist_apply_for_all() - apply a function to every request.188 * @rl: the requestlist that contains the target requests.189 * @f: the function to apply to each request; the first parameter of the190 * function will be the target-request; the second parameter is the same191 * pointer as given with the argument @data.192 * @data: freely chosen argument; passed through to @f as second parameter.193 *194 * Uses :c:macro:`list_for_each_entry` to iterate over the lists in the hash-195 * table (not a 'safe' variant, so don't modify the list).196 *197 * Holds @rl->lock over the entire request-iteration.198 */199static inline void200zfcp_reqlist_apply_for_all(struct zfcp_reqlist *rl,201 void (*f)(struct zfcp_fsf_req *, void *), void *data)202{203 struct zfcp_fsf_req *req;204 unsigned long flags;205 size_t i;206 207 spin_lock_irqsave(&rl->lock, flags);208 for (i = 0; i < ZFCP_REQ_LIST_BUCKETS; i++)209 list_for_each_entry(req, &rl->buckets[i], list)210 f(req, data);211 spin_unlock_irqrestore(&rl->lock, flags);212}213 214#endif /* ZFCP_REQLIST_H */215